Power storage device

ABSTRACT

In the field of portable electronic devices in the future, portable electronic devices will be desired, which are smaller and more lightweight and can be used for a long time period by one-time charging, as apparent from provision of one-segment partial reception service “1-seg” of terrestrial digital broadcasting that covers the mobile objects such as a cellular phone. Therefore, the need for a power storage device is increased, which is small and lightweight and capable of being charged without receiving power from commercial power. The power storage device includes an antenna for receiving an electromagnetic wave, a capacitor for storing power, and a circuit for controlling store and supply of the power. When the antenna, the capacitor, and the control circuit are integrally formed and thinned, a structural body formed of ceramics or the like is partially used. A circuit for storing power of an electromagnetic wave received at the antenna in a capacitor and a control circuit for arbitrarily discharging the stored power are provided, whereby lifetime of the power storage device can be extended.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a power storage device capable of beingcharged without receiving power from commercial power.

2. Description of the Related Art

Electronic devices such as a cellular phone, a mobile computer, adigital camera, and a digital audio player have been advanced to bedownsized, and a large variety of products have been shipped to themarket. In such portable electronic devices, a secondary battery as apower supply for driving is incorporated. As a secondary battery, alithium-ion battery, a nickel-hydrogen battery, or the like is used. Thesecondary battery is charged by receiving power from commercial power.For example, a user connects an AC adapter to a household plug socketdeposited in each home to charge the secondary battery.

Although portable electronic devices are convenient, the hour of use isrestricted by the capacity of the secondary battery. The user of theelectronic device needs to pay attention to remaining battery level ofthe secondary battery and to be always conscious of the charging time.Further, the charging plugs of the electronic devices are different foreach device or for each model. Therefore, many AC adapters are requiredto be possessed.

In contrast, a power storage device is disclosed, in which a permanentmagnet is moved back and forth in a slide where a coil is rolled togenerate electromagnetic induced electromotive force, whereby the powerstorage device is charged (for example, Reference 1: Japanese PublishedPatent Application No. 2006-149163 (FIG. 1, and p. 4)). According tothis device, power storage devices are considered to be capable of beingcharged without receiving power from commercial power supply.

SUMMARY OF THE INVENTION

However, the power storage device utilizing electromagnetic inducedelectromotive force generated by a coil and a permanent magnet needs amovable portion, and therefore, downsizing of the power storage deviceis structurally difficult. Moreover, such a power storage device isrequired to move the magnet as well as to possess it, and the weight ofthe device is increased because the permanent magnet is used. Therefore,the conventional power storage device has a problem that the volume andthe weight thereof are increased, and portability is lost.

Incidentally, in the field of portable electronic devices in the future,portable electronic devices will be desired, which are smaller and morelightweight and can be used for a long time period by one-time charging,as apparent from provision of one-segment partial reception service“1-seg” of terrestrial digital broadcasting that covers the mobileobjects such as a cellular phone. Therefore, the need for the powerstorage device is increased, which is small and lightweight and capableof being charged without receiving power from commercial power.

It is an object of the present invention to provide a power storagedevice that can be charged without receiving power from commercialpower, in which the charging is performed easily while reduction in sizeand weight or reduction in weight and thickness is achieved. It isanother object of the present invention to maintain durability andrequired functions in the case where such a power storage device becomessmall and downsized.

The present invention is to provide a power storage device including anantenna for receiving an electromagnetic wave, a capacitor for storingpower, and a circuit for controlling store and supply of power. In acase where the antenna, the capacitor, and the control circuit areintegrally formed and thinned, a structural body formed of ceramics orthe like is used for part of the integral structure.

The structural body formed of ceramics or the like has resistance topressing force or bending stress applied from outside. Therefore, in thecase of thinning the antenna and the control circuit, the structuralbody formed of ceramics or the like serves as a protector. In addition,this structural body can have a function as a capacitor.

According to the present invention, a circuit for storing power of anelectromagnetic wave received at an antenna in a capacitor and a controlcircuit for discharging the given power are provided, whereby lifetimeof the power storage device can be extended.

When the structural body formed of ceramics or the like is used for partof the power storage device, rigidity can be improved. Accordingly, evenwhen the power storage device is thinned, durability and requiredfunctions can be maintained.

For example, even when pressing force is applied with a pointed objectsuch as a tip of a pen, malfunction due to stress applied to thecapacitor and the control circuit can be prevented. Moreover, resistanceto bending stress can also be provided. In addition, when a wiring forconnection is formed in the structural body formed of ceramics or thelike so that the antenna and the control circuit are connected,malfunction caused by detachment of a connection portion can beprevented even when bending stress is applied.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view showing one mode of a power storage device of thepresent invention.

FIG. 2 is a cross-sectional view showing an example of a structure takenalong a line A-B of FIG. 1.

FIG. 3 is a cross-sectional view showing an example of a structure takenalong a line A-B of FIG. 1.

FIGS. 4A to 4C are plan views showing an example of a power storagedevice that includes a first structural body provided with an antenna, asecond structural body provided with a capacitor, and a power supplycontrol circuit.

FIGS. 5A and 5B are cross-sectional views showing an example of a powerstorage device that includes a first structural body provided with anantenna, a second structural body provided with a capacitor, and a powersupply control circuit.

FIGS. 6A to 6D are plan views showing an example of a power storagedevice that includes a first structural body provided with an antenna, asecond structural body provided with a capacitor, a power supply controlcircuit, and a ceramics antenna.

FIGS. 7A and 7B are cross-sectional views showing an example of a powerstorage device that includes a first structural body provided with anantenna, a second structural body provided with a capacitor, a powersupply control circuit, and a ceramics antenna.

FIG. 8 is a view showing an example of a power supply control circuit ina power storage device.

FIG. 9 is a view showing an output waveform of a low-frequency signalgeneration circuit.

FIG. 10 is a view showing a structure of a low-frequency signalgeneration circuit of a power supply control circuit in a power storagedevice.

FIG. 11 is a timing chart of a signal output from the low-frequencysignal generation circuit shown in FIG. 10.

FIG. 12 is a diagram showing a structure of a power supply circuit of apower supply control circuit in a power storage device.

FIG. 13 is a view showing a structure of a power storage device providedwith a plurality of antennas.

FIG. 14 is a view showing a structure of a power storage device having afunction of controlling supply of power stored in a capacitor.

FIG. 15 is a view showing a structure of a control circuit of a powersupply control circuit in a power storage device.

FIG. 16 is a view showing a structure of a voltage-comparing circuit ofa power supply control circuit in a power storage device.

FIG. 17 is a cross-sectional view for explaining a structure of a thinfilm transistor used for forming a power supply control circuit.

FIG. 18 is a cross-sectional view for explaining a structure of a MOStransistor used for forming a power supply control circuit.

FIG. 19 is a block diagram showing a structure of an active wirelesstag.

FIG. 20 is a view showing an example of distribution management using anactive wireless tag.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, an embodiment mode and embodiments of the present inventionis described below with reference to the accompanying drawings. Notethat the present invention is not limited to the following descriptionand it is easily understood by those skilled in the art that modes anddetails can be modified in various ways without departing from thepurpose and the scope of the present invention. Accordingly, the presentinvention should not be interpreted as being limited to the descriptionof the embodiment mode below. Note that like portions in the drawingsmay be denoted by the like reference numerals in a structure of thepresent invention to be given below.

A power storage device of the present invention includes a firststructural body provided with an antenna, a power supply control circuitformed using a semiconductor layer interposed between insulating layersthat are provided over and below the semiconductor layer, and a secondstructural body provided with a capacitor and having higher rigiditythan the first structural body. This second structural body includes atleast a dielectric layer inside, and the capacitor is preferably formedusing the dielectric layer. The second structural body is formed ofceramics or the like, which has high rigidity, whereby mechanicalstrength of the power storage device can be maintained even when thepower supply control circuit is thinned.

FIG. 1 shows one mode of such a power storage device. A first structuralbody 10 is formed of an insulating material. The thickness of the firststructural body 10 is 1 μm to 100 μm, preferably, 5 μm to 30 μm. As theinsulating material, a plastic sheet, a plastic film, a glass epoxyresin, a glass plate, paper, a nonwoven fabric, or other variety ofobjects can be used. An antenna 16 is formed using a conductive materialat least on one of surfaces of the first structural body 10. A structureof the antenna is preferably differentiated depending on a frequencyband of an electromagnetic wave used by the power storage device. Theantenna may have a suitable shape for a frequency band, when a frequencyin a short wave band (electromagnetic wave with frequency of 1 to 30MHz), an ultrashort wave band (electromagnetic wave with frequency of 30to 300 MHz), or a microwave band (electromagnetic wave with frequency of0.3 to 3 GHz) is used. FIG. 1 shows a dipole antenna, which is suitedfor communication in the ultrashort wave band and the microwave band. Amonopole antenna, a patch antenna, a spiral antenna, a loop antenna, orthe like can be used as the antenna, other than the dipole antenna shownin FIG. 1.

The antenna 16 is provided with an antenna terminal 18 in order to beconnected to a power supply control circuit 14. The power supply controlcircuit 14 is formed so that at least a part thereof overlaps with thefirst structural body 10. A second structural body 12 is used as aconnector for tightening connection of the first structural body 10 andthe power supply control circuit 14.

FIG. 2 shows a cross-sectional structure of the power storage devicetaken along a line A-B of FIG. 1. The second structural body 12 islocated to face one side on which the antenna terminal 18 of the firststructural body 10 is formed. The power supply control circuit 14 islocated to face the other side of the second structural body 12. Athrough electrode 20 is formed in the second structural body 12 at aposition corresponding to that of the antenna terminal 18. The throughelectrode 20 is formed so as to be connected to a connection electrode24 of the power supply control circuit 14 on the other side of thesecond structural body 12. The through electrode 20 is formed using ametal foil or metal paste in a through hole formed in the secondstructural body 12.

The second structural body 12 has a thickness of 0.1 μm to 50 μm,preferably 5 μm to 30 μm, and is preferably harder than the firststructural body 10. In addition, the second structural body 12preferably has toughness and elasticity to certain bending stress. Thisis because in a case where the first structural body 10 is formed of aflexible material such as a plastic film or a nonwoven fabric, bendingstress can be dispersed when the second structural body 12 has uniformelasticity. Accordingly, disconnection failure between the antennaterminal 18 and the connection electrode 24 which are connected via thethrough electrode 20 can be prevented. In addition, when the throughelectrode 20 is formed in the second structural body 12, the powersupply control circuit 14 can be downsized.

As the second structural body 12, an insulating substance such as hardplastics or glass can be used, and in particular, the ceramic materialis preferably used. This is because the ceramic material realizes theforegoing characteristics and therefore, the material to be used can beselected from a wide range of materials. Further, a plurality ofceramics can be combined to be a compound.

As a typical example of the ceramic material, alumina (Al₂O₃) ispreferably used as a highly insulating material. In addition, bariumtitanate (BaTiO₃) is preferably used as a high capacitance material.When mechanical strength has higher priority, alumina (Al₂O₃), titaniumoxide (TiO_(x)), silicon carbide (SiC), tempered glass, or crystallizedglass is preferably used. In addition, when composite ceramics in whichnanoparticles of SiC are added to Si₃N₄, or composite ceramics whichcontains hexagonal system BN is used, high strength, oxidationresistance, and high toughness can be obtained, which is preferable.

These ceramic materials may be used to form a stacked layer structure ofa plurality of layers each having a thickness of 0.1 μm to 2 μm in thesecond structural body 12. In other words, it is preferable that astacked-layer substrate be formed and an electrode be formed in eachlayer to form a stacked layer capacitor in the second structural body12.

The power supply control circuit 14 is formed using an active elementformed of a semiconductor layer having a thickness of 5 nm to 500 nm,preferably, 30 nm to 150 nm. Over and below the semiconductor layer,insulating layers are provided. These insulating layers are formed aslayers for protecting the semiconductor layer. In addition, they may beused as a functional layer such as a gate insulating layer. A typicalexample of an active element is a field-effect transistor. Since thesemiconductor layer is a thin film as described above, a field-effecttransistor formed here is also referred to as a thin film transistor.The semiconductor layer is preferably a crystalline semiconductor layerthat is crystallized by heat treatment or energy beam irradiation with alaser beam or the like, after a semiconductor layer is formed by a vapordeposition method, a sputtering method, or the like. This is becausewhen a crystalline semiconductor layer is formed, field-effect mobilityof the field-effect transistor becomes 30 to 500 cm²/V·sec (electron),which suppresses power loss.

The power supply control circuit 14 includes a semiconductor layer, aninsulating layer, a layer for forming a wiring, and is preferably formedto have a thickness of 0.5 μm to 5 μm in total. When the power supplycontrol circuit 14 is formed to have this thickness, the power supplycontrol circuit 14 can contribute to reduction in thickness of the powerstorage device. Further, the power supply control circuit 14 can haveresistance to bending stress. When the semiconductor layer is separatedto be island-shaped semiconductor layers, resistance to bending stresscan be improved.

The first structural body 10 and the second structural body 12 are fixedby an adhesive 28 so that the antenna terminal 18 and the throughelectrode 20 are electrically connected. For example, as the adhesive28, an acrylic-based, urethane-based, or epoxy-based adhesive, in whichconductive particles are dispersed, can be used. Alternatively, aconnection portion of the antenna terminal 18 and the through electrode20 may be fixed by a conductive paste or a solder paste and another partmay be fixed by acrylic-based, urethane-based, or epoxy-based adhesive.Also, the second structural body 12 and the power supply control circuit14 are fixed so that the through electrode 20 and the connectionelectrode 24 are electrically connected.

A sealant 30 is formed using an acrylic-based, urethane-based,phenol-based, epoxy-based, or silicone-based resin material and ispreferably provided in order to protect the power supply control circuit14. The sealant 30 is formed to cover the power supply control circuit14 and to preferably cover side surfaces of the power supply controlcircuit 14 and the second structural body 12. When the sealant 30 isprovided, the power supply control circuit 14 can be prevented frombeing damaged. Further, the adhesive strength between the power supplycontrol circuit 14, the second structural body 12, and the firststructural body 10 can be enhanced. In such a way, a power storagedevice with a thickness of 2 μm to 150 μm, preferably, 10 μm to 60 μmcan be obtained.

FIG. 3 shows a structure in which the antenna terminal 18 of the firststructural body 10 and the connection electrode 24 of the power supplycontrol circuit 14 are located to face and be connected to each other.The second structural body 12 is located on a back side of the powersupply control circuit 14 so as to protect the power supply controlcircuit 14. In a case where the second structural body 12 is providedwith a capacitor, a ceramics antenna-connection electrode 27 may beformed in the power supply control circuit 14 so as to be electricallyconnected to a capacitor external electrode 22 of the second structuralbody 12. The first structural body 10, the second structural body 12,and the power supply control circuit 14 are preferably fixed by theadhesive 28. In a structure shown in FIG. 3, since the second structuralbody 12 is located on the back side of the power supply control circuit14, the sealant 30 may be provided as appropriate.

As described above, according to the present invention, when thestructural body formed of ceramics or the like is used, rigidity of thepower storage device can be improved. Accordingly, even when the powerstorage device is thinned, durability and required functions can bemaintained. When a wiring for connection is formed in the structuralbody formed of ceramics or the like and an antenna and a power supplycontrol circuit are connected, malfunction caused by detachment of aconnection portion can be prevented even when bending stress is applied.

EMBODIMENT 1

This embodiment will explain an example of a power storage device thatincludes a first structural body provided with an antenna, a secondstructural body provided with a capacitor, and a power supply controlcircuit 14, with reference to FIGS. 4A to 4C and FIGS. 5A and 5B. FIGS.4A to 4C are plan views of the power storage device, and FIGS. 5A and 5Bare cross-sectional views taken along lines A-B and C-D of FIG. 4A.

FIG. 4A shows a mode in which an antenna 16 having a coil-shape isformed in a first structural body 10. The first structural body 10 isformed using a plastic material such as PET (polyethyleneterephthalate), PEN (polyethylene naphthalate), PES (polyethersulfone),polypropylene, polypropylene sulfide, polycarbonate, polyether imide,polyphenylene sulfide, polyphenylene oxide, polysulfone,polyphthalamide, acrylic, or polyimide, or an insulating material suchas nonwoven fabric, or paper.

The antenna 16 is formed in the first structural body 10 using a lowresistance metal material such as copper, silver, or aluminum, by aprinting method, a plating method, or the like. The antenna 16 shown inFIG. 4A has a coil-shape which is suitable when an electromagneticinduction method (for example, 13.56 MHz band) is employed. When amicrowave method (for example, an UHF band (860 to 960 MHz band), 2.45GHz band, or the like) is employed, a length and a shape of a conductivelayer serving as antenna may be appropriately set in consideration of awavelength of an electromagnetic wave that is used for transmittingsignals. In this case, a monopole antenna, a dipole antenna, a patchantenna, and the like may be used.

FIG. 4A shows a mode in which a second structural body 12 and a powersupply circuit 14 are provided in accordance with an antenna terminal18. FIG. 4B is a plan view of the second structural body 12, and FIG. 4Cis a plan view of the power control circuit 14. An outside dimension ofthe second structural body 12 and that of the power supply controlcircuit 14 are preferably almost the same. Alternatively, the outsidedimension of the power supply control circuit 14 may be smaller thanthat of the second structural body 12.

In this embodiment, the second structural body 12 is preferably formedof a ceramic material. In this second structural body 12, a throughelectrode 20 and a capacitor electrode 34 are formed. In the powersupply control circuit 14, a connection electrode 24 that is connectedto the antenna terminal 18 and a capacitor-portion connection electrode26 that is connected to the capacitor electrode 34 are formed.Subsequently, the details of a connection structure of the secondstructural body 12 and the power supply control circuit 14 is explainedwith reference to FIGS. 5A and 5B.

FIG. 5A is a cross-sectional view taken along a line A-B. The firststructural body 10 and the power supply control circuit 14 are connectedto each other by the through electrode 20 formed in the secondstructural body 12. They are fixed by an adhesive 28. In the secondstructural body 12, layers each including a dielectric layer 32 and thecapacitor electrode 34 are stacked so as to be engaged with each other.A capacitor is formed by stacking the dielectric layer 32 and thecapacitor electrode 34 in such a manner.

The dielectric layer 32 is formed by coating a surface of the substratewith a ceramics paste in which a ceramic material such as bariumtitanate (BaTiO₃), strontium titanate (SrTiO₃), or a Pb-based complexperovskites compound material contains a binder compound, a plasticizer,and an organic solvent. Then, an electrode paste selected from copper ora copper alloy, nickel or a nickel alloy, silver or a silver alloy, andtin or a tin alloy, is printed thereover to form the capacitor electrode34. Note that when the through electrode 20 is formed, the dielectriclayer and the capacitor electrode are formed to have an opening in acorresponding position where the through electrode 20 is formed. Thedielectric layer and the capacitor electrode are dried, and then, cutinto predetermined shapes. Then, the capacitor electrodes 34 are stackedto be engaged with each other. The stacked layers are interposed betweenprotective layers 36 formed of a ceramic material or the like, thebinder is removed, and baking and heating treatment are performed toform the capacitor.

In FIGS. 5A and 5B, the dielectric layer 32 and the capacitor electrode34 can be formed to have a thickness of 1 to 10 μm by usingnanoparticles. Accordingly, when five dielectric layers 32 each having athickness of 2 μm are stacked, the thickness thereof is 10 μm. Further,even when ten dielectric layers 32 each having a thickness of 1 μm arestacked, the thickness thereof is not greater than 10 μm.

FIG. 5B is a cross-sectional view taken along a line C-D and shows astructure of the capacitor electrode 34 and the capacitor-portionconnection electrode 26 of the power supply control circuit 14. In thesecond structural body 12, a capacitor external electrode 22, which isformed in an outer edge portion, is subjected to nickel plating, tinplating, and the like The adhesive 28 can be used for connecting thecapacitor external electrode 22 and the capacitor-portion connectionelectrode 26.

As descried above, the power storage device that includes the firststructural body 10 provided with an antenna, the second structural body12 provided with a capacitor, and the power supply control circuit 14can be obtained. When the second structural body 12 formed of ceramicsor the like is used, rigidity of the power storage device can beimproved. Accordingly, even when a power storage device including thepower supply control circuit 14 is thinned, durability and requiredfunctions can be maintained.

EMBODIMENT 2

This embodiment will explain an example of a power storage device of thepresent invention provided with a plurality of antennas. An example of apower storage device will be explained with reference to FIGS. 6A to 6Dand FIGS. 7A and 7B, which includes a first structural body 10 providedwith an antenna, a second structural body 12 provided with a capacitor,a power supply control circuit 14, and a ceramics antenna 38. FIGS. 6Ato 6D are plan views of the power storage device, and FIGS. 7A and 7Bare cross-sectional views taken along lines E-F and G-H.

In FIG. 6A, an antenna 16 having a coil-shape is formed in the firststructural body 10. The shape of the antenna 16 may be appropriately setin accordance with a frequency band that is used for communication,similarly to in Embodiment 1.

FIG. 6A shows a mode in which the second structural body 12, the powersupply control circuit 14, and the ceramics antenna 38 are provided inaccordance with an antenna terminal 18. FIG. 6B is a plan view of thesecond structural body 12, FIG. 6C is a plan view of the power supplycontrol circuit 14, and FIG. 6D is a plan view of the ceramics antenna38. Outside dimensions of the second structural body 12, the powersupply control circuit 14, and the ceramics antenna 38 are preferablyalmost the same. Alternatively, the outside dimension of the powersupply control circuit 14 may be smaller than those of the secondstructural body 12 and the ceramics antenna 38.

In the second structural body 12 that is formed of a ceramic material, athrough electrode 20 and a capacitor external electrode 22 are formed.In the power supply control circuit 14, a connection electrode 24 thatis connected to the antenna terminal 18, a capacitor-portion connectionelectrode 26 that is connected to the capacitor external electrode 22,and a ceramics antenna-connection electrode 27 that is connected to theceramics antenna 38 are formed. Subsequently, the details of connectionstructures of the second structural body 12 and the power supply controlcircuit 14 are explained with reference to FIGS. 7A and 7B.

FIG. 7A is a cross-sectional view taken along a line E-F. In the secondstructural body 12, a capacitor is formed using a ceramic material,similarly to Embodiment 1. The structure including the through electrode20 that connects the antenna terminal 18 of the first structural body 10and the connection electrode 24 of the power supply control circuit 14,is similar to that of FIG. 5A. The ceramics antenna 38 is located on theback side of the power supply control circuit 14. The second structuralbody 12 and the ceramics antenna 38, sandwiching the power supplycontrol circuit 14, have a function for a protective layer.

FIG. 7B is a cross-sectional view taken along a line G-H and shows aconnection structure between the power supply control circuit 14 and theceramics antenna 38. The ceramics antenna 38 includes a ground body 44on one side of a dielectric substance 42 (the power supply controlcircuit 14 side) and a reflector 46 on the other side. The power supplycontrol circuit 14 is provided with the ceramics antenna-connectionelectrode 27 to which the ground body 44 and a power feeding body 40 areconnected. The reflector 46 may have a slit to enhance directivity. Thereflector 46 and the power feeding body 40 are provided with a gaptherebetween and are capacitive coupled.

In the power storage device of this embodiment, the antenna 16 formed inthe first structural body 10 and the ceramics antenna 38 are used as anantenna for power feeding, and the power is stored in the capacitorformed in the second structural body 12. The capacitor includesdielectric layers 32 and capacitor electrodes 34. Large capacitance canbe obtained by stacking a plurality of dielectric layers 32 andcapacitor electrodes 34. In this case, frequencies of an electromagneticwave received at the antenna 16 and the ceramics antenna 38 are varied,whereby the capacitor can be efficiently charged. In other words, a bandof the electromagnetic wave received for charging the capacitor can beextended. In this case, the dielectric layer 32 and the capacitorelectrode 34 can be formed to have a thickness of 1 to 10 μm by usingnanoparticles. Accordingly, when five dielectric layers 32 each having athickness of 2 μm are stacked, the thickness thereof is 10 μm. Further,even when ten dielectric layers 32 each having a thickness of 1 μm arestacked, the thickness thereof is not greater than 10 μm.

As described above, the power storage device including the firststructural body 10 provided with an antenna, the second structural body12 provided with a capacitor, the power supply control circuit 14, andthe ceramics antenna 38 can be obtained. When the second structural body12 formed of ceramics or the like and the ceramics antenna 38 are used,rigidity of the power storage device can be improved. Accordingly, evenwhen a power storage device including the power supply control circuit14 is thinned, durability and required functions can be maintained.

EMBODIMENT 3

An example of a power supply control circuit of a power storage deviceof the present invention will be explained with the use of a blockdiagram shown in FIG. 8.

A power storage device 100 of FIG. 8 includes an antenna 102, a powersupply control circuit 104, and a capacitor 106. The power supplycontrol circuit 104 includes a rectifier circuit 108, a low-frequencysignal generation circuit 110, a switching circuit 112, and a powersupply circuit 114. Power is output from the power supply circuit in thepower supply control circuit to a load 118 on the outside of the powerstorage device.

The antenna 102 is formed in the first structural body 10 in accordancewith Embodiment 1. The capacitor 106 is formed in the second structuralbody 12. The power supply control circuit 104 corresponds to the powersupply control circuit 14.

A structure of the load 118 in FIG. 8 is different depending onelectronic devices. For example, in the cellular phones and the digitalvideo cameras, a logic circuit, an amplifier circuit, a memorycontroller, and the like correspond to a load. Also, in IC cards, ICtags, and the like, a high-frequency circuit, a logic circuit, and thelike correspond to a load.

Further, FIG. 8 is the power storage device 100 having a structure inwhich an electromagnetic wave supplied by a power feeder 120 is receivedat the antenna 102 and stored in the capacitor 106. In FIG. 8, theelectromagnetic wave received at the antenna 102 is rectified at therectifier circuit 108 and stored in the capacitor 106. Power obtained byreceiving the electromagnetic wave at the antenna 102 is input to thelow-frequency signal generation circuit 110 through the rectifiercircuit 108. Further, power obtained by receiving the electromagneticwave at the antenna 102 is input to the power supply circuit 114 throughthe rectifier circuit 108 and the switching circuit 112 as a signal. Thelow-frequency signal generation circuit 110 outputs an on/off controlsignal to the switching circuit 112 when operation of the low-frequencysignal generation circuit 110 is controlled by the input signal.

In FIG. 8, the power obtained by receiving the electromagnetic wave isstored in the capacitor 106. When the power is not sufficiently suppliedfrom the power feeder 120, power supplied from the capacitor 106 issupplied to the power supply circuit 114 through the switching circuit112. The power feeder 120 is a device for emitting an electromagneticwave that can be received at the antenna 102.

A structure of the antenna 102 in FIG. 8 may be selected from anelectromagnetic coupling method, an electromagnetic induction method, amicro-wave method or the like, depending on a frequency band of theelectromagnetic wave that is received. The antenna 102 can arbitrarilyreceive an electromagnetic wave and supply a signal to the power supplycontrol circuit 104, regardless of whether or not an electromagneticwave supplied by the power feeder 120 exists. For example, anelectromagnetic wave of a cellular phone (800 to 900 MHz band, 1.5 GHz,1.9 to 2.1 GHz band, or the like), an electromagnetic wave oscillatedfrom the cellular phone, an electromagnetic wave of a radio wave clock(40 kHz or the like), noise of a household AC power supply (60 Hz or thelike), electromagnetic waves that are randomly generated from otherwireless signal output means, and the like can be utilized as anelectromagnetic wave received at the antenna 102 in order to be storedin the capacitor 106 of the power storage device 100.

Next, operation for charging the capacitor 106 and supplying power tothe power supply circuit 114 by receiving an electromagnetic wave in thepower storage device 100 of FIG. 8 will be explained. Theelectromagnetic wave received at the antenna 102 is half-wave rectifiedand smoothed by the rectifier circuit 108. Then, the power output fromthe rectifier circuit 108 is supplied to the power supply circuit 114through the switching circuit 112, and surplus power is stored in thecapacitor 106.

In the power storage device 100 of this embodiment, by intermittentlyoperating the power storage device 100 depending on strength of theelectromagnetic wave, it is attempted that power stored in the capacitor106 is not consumed wastefully. Although the power storage circuitgenerally supplies continuous power to a load, continuous power is notalways necessary to be supplied depending on use application. In such acase, operation of supplying power from the power storage device 100 isstopped, whereby consumption of the power stored in the capacitor 106can be suppressed. In this embodiment, only the low-frequency signalgeneration circuit 110 in FIG. 8 operates continuously. Thelow-frequency signal generation circuit 110 operates based on the powerstored in the capacitor 106. An output waveform of the low-frequencysignal generation circuit 110 is explained with reference to FIG. 9.

FIG. 9 shows a waveform of a signal that is output from thelow-frequency signal generation circuit 110 to the switching circuit. Inan example of FIG. 9, a duty ratio of the output waveform is set 1:n (nis an integer) so that power consumption can be set approximately1/(n+1). The switching circuit 112 is driven in accordance with thissignal. The switching circuit 112 connects the capacitor 106 and thepower supply circuit 114 only during a period where the output signal ishigh; therefore, power is supplied to a load through the power supplycircuit from a battery in the power storage device only during theperiod.

FIG. 10 shows an example of the low-frequency signal generation circuit110 of FIG. 8. The low-frequency signal generation circuit 110 in FIG.10 includes a ring oscillator 122, a frequency-divider circuit 124, anAND circuit 126, and inverters 128 and 130. An oscillation signal of thering oscillator 122 is frequency-divided with the frequency-dividercircuit 124 and the output thereof is input into the AND circuit 126 togenerate a low-duty ratio signal with the AND circuit 126. Further, theoutput of the AND circuit 126 is input to a switching circuit 112including a transmission gate 132 through the inverters 128 and 130. Thering oscillator 122 oscillates with a low frequency, and oscillation isperformed at 1 kHz, for example.

FIG. 11 is a timing chart of a signal output from the low-frequencysignal generation circuit 110 shown in FIG. 10. FIG. 11 shows an exampleof an output waveform of the ring oscillator 122, an output waveform ofthe frequency-divider circuit 124, and an output waveform of the ANDcircuit 126. In FIG. 11, an output waveform is shown, in which a signaloutput from the ring oscillator 122 is frequency-divided, where thenumber of division is 1024. As the output waveform, a frequency-dividercircuit output waveform 1, a frequency-divider circuit output waveform2, and a frequency-divider circuit output waveform 3 are sequentiallyoutput. When these output waveforms are processed with the AND circuit126, a signal with a duty ratio of 1:1024 can be formed. As long as theoscillation frequency of the ring oscillator 122 is 1 KHz at this time,an operation period is 0.5 μsec, and a non-operation period is 512 μsecin one cycle.

The signal output from the low-frequency signal generation circuit 110regularly controls on/off of the transmission gate 132 of the switchingcircuit 112 and controls supply of the power from the capacitor 106 tothe power supply circuit 114. Therefore, supply of the power from thepower storage device 100 to the load can be controlled. In other words,the power is intermittently supplied from the capacitor 106 to a signalcontrol circuit portion, whereby supply of the power from the powerstorage device 100 to the load 118 can be suppressed, and low powerconsumption can be achieved.

An example of the power supply circuit 114 in FIG. 8 is explained withreference to FIG. 12. The power supply circuit 114 comprises a referencevoltage circuit and a buffer amplifier. The reference voltage circuitincludes a resistor 134, and transistors 136 and 138 that arediode-connected. In this circuit, a reference voltage (2×Vgs)corresponding to a voltage between a gate and a source (Vgs) of thetransistor is generated by the transistors 136 and 138. The bufferamplifier includes a differential circuit that includes transistors 140and 142, a current mirror circuit that includes transistors 144 and 146,a current supply resistor 148, and a common source amplifier thatincludes a transistor 150 and a resistor 152.

The power supply circuit 114 shown in FIG. 12 operates in such a mannerthat when a large amount of current is output from an output terminal,the amount of current that flows through the transistor 150 becomessmall, whereas when a small amount of current is output from the outputterminal, the amount of current that flows through the transistor 150becomes large. Thus, a current that flows through the resistor 152 isalmost constant. In addition, the potential of the output terminal isalmost the same as that of the reference voltage circuit. Here, althoughthe power supply circuit including the reference voltage circuit and thebuffer amplifier is shown, the power supply circuit 114 is not limitedto the structure in FIG. 12, and a power supply circuit with a differentstructure may be used.

As described above, the power supply control circuit of this embodimentcan be applied to the power storage device of Embodiment 1. According tothe power supply control circuit of this embodiment, an electromagneticwave can be received and used as power to be stored in the capacitor.The power stored in the capacitor 106 can be supplied to a load. Inaddition, supply of the power from the power storage device to the loadcan be controlled. In other words, the power is intermittently suppliedfrom the capacitor to the signal control circuit portion, whereby supplyof the power from the power storage device to the load is suppressed,and power consumption can be reduced.

EMBODIMENT 4

This embodiment will explain an example of a power storage devicecorresponding to Embodiment 2 with reference to FIG. 13. Note thatdifferent points from FIG. 8 will be mainly explained below.

A structure of a power storage device provided with a plurality ofantenna circuits is shown in FIG. 13. An antenna 102 and a secondantenna 103 are provided as the plurality of antenna circuits, which isdifferent point from FIG. 8. The antenna 102 and the second antenna 103are preferably formed so that compatible reception frequencies aredifferent from each other. For example, the antenna 102 can formed of aspiral antenna as shown in FIG. 6A of Embodiment 2, and the secondantenna 103 can be formed of a ceramics antenna (patch antenna).

The antenna 102 is formed in the first structural body 10 in accordancewith Embodiment 2. The second antenna 103 corresponds to the ceramicsantenna 38. A capacitor 106 is formed in the second structural body 12.A power supply control circuit 104 corresponds to the power supplycontrol circuit 14.

Electromagnetic waves received at the antenna 102 and the second antenna103 are rectified at a rectifier circuit 108 and stored in the capacitor106. In the rectifier circuit 108, the electromagnetic waves received atboth antennas can be rectified concurrently and stored in the capacitor106. Alternatively, one of the electromagnetic waves received at theantenna 102 and the second antenna 103, which has stronger fieldintensity than the other, may be preferentially rectified at therectifier circuit 108 to be stored in the capacitor 106.

Another structure of the power storage device 100 in this embodiment isthe same as that of FIG. 8, and a similar operation effect can beobtained.

EMBODIMENT 5

This embodiment shows a power storage device having a function forcontrolling supply of power that is stored in a capacitor. Note that theportion having a similar function as that shown in Embodiment 3 isdenoted by the same reference numeral to explain this embodiment.

A power storage device 100 of FIG. 14 includes an antenna 102, a powersupply control circuit 104, and a capacitor 106. The power supplycontrol circuit 104 includes a rectifier circuit 108, a control circuit116, a low-frequency signal generation circuit 110, a switching circuit112, and a power supply circuit 114. Power is supplied from the powersupply circuit 114 to a load 118.

The antenna 102 is formed in the first structural body 10 in accordancewith Embodiment 1. The capacitor 106 is formed in the second structuralbody 12. The power supply control circuit 104 corresponds to the powersupply control circuit 14.

In the power storage device of this embodiment, when power output fromthe rectifier circuit 108 exceeds power consumption of the load 118, thepower supply control circuit 104 stores the excess power in thecapacitor 106. Alternatively, when power that is output from therectifier circuit 108 is insufficient for power consumption of the load118, the power supply control circuit 104 discharges the capacitor 106so that power is supplied to the power supply circuit 114. In FIG. 14, acontrol circuit 116 at the subsequent stage of the rectifier circuit 108is provided for performing such operation.

In FIG. 15, an example of the control circuit 116 is shown. The controlcircuit 116 includes switches 154 and 156, rectifier elements 158 and160, and a voltage comparator circuit 162. In FIG. 15, the voltagecomparator circuit 162 compares a voltage output from the capacitor 106with a voltage output from the rectifier circuit 108. When a voltageoutput from the rectifier circuit 108 is sufficiently higher than avoltage output from the capacitor 106, the voltage comparator circuit162 turns the switch 154 on and turns the switch 156 off. In such acondition, a current flows in the capacitor 106 from the rectifiercircuit 108 through the rectifier element 158 and the switch 154. On theother hand, when a voltage output from the rectifier circuit 108 isinsufficient as compared with a voltage output from the capacitor 106,the voltage comparator circuit 162 turns the switch 154 off and turnsthe switch 156 on. At this time, when a voltage output from therectifier circuit 108 is higher than a voltage output from the capacitor106, a current does not flow in the rectifier element 160; however, whena voltage output from the rectifier circuit 108 is lower than a voltageoutput from a battery, a current flows in the switch circuit 112 fromthe capacitor 106 through the switch 156 and the rectifier element 160.

FIG. 16 shows a structure of the voltage comparator circuit 162. In thestructure shown in FIG. 16, the voltage comparator circuit 162 dividesthe voltage output from the capacitor 106 with resistor elements 164 and166, and divides the voltage output from the rectifier circuit 108 withresistor elements 168 and 170. Then, the voltage comparator circuit 162inputs the divided voltage into a comparator 172. Inverter-type buffercircuits 174 and 176 are connected in series by an output of thecomparator 172. Then, an output of the buffer circuit 174 is input to acontrol terminal of the switch 154, and an output of the buffer circuit176 is input to a control terminal of the switch 156, whereby on/off ofthe switches 154 and 156 is controlled. For example each of the switches154 and 156 is turned on when an output of the buffer circuit 174 or 176is at the high potential (“H” level), and each of the switches 154 and156 is turned off when an output of the buffer circuit 174 or 176 is atthe low potential (“L” level). In such a manner, each voltage of thecapacitor 106 and the rectifier circuit 108 is divided with the resistorto be input into the comparator 172, whereby on/off of the switches 154and 156 can be controlled.

Note that the control circuit 116 and the voltage comparator circuit 162are not limited to the above structure, and other types of controlcircuits and voltage comparator circuits may be used as long as theyhave various functions.

Operation of the power storage device 100 shown in FIG. 14 is generallyas follows. First, an external wireless signal received at the antenna102 is half-waved rectified by the rectifier circuit 108 and thensmoothed. Then, a voltage output from the capacitor 106 and a voltageoutput from the rectifier circuit 108 are compared at the controlcircuit 116. When the voltage output from the rectifier circuit 108 issufficiently higher than the voltage output from the capacitor 106, therectifier circuit 108 is connected to the capacitor 106. At this time,power output from the rectifier circuit 108 is supplied to the capacitor106 and the power supply circuit 114, and surplus power is stored in thecapacitor 106.

The control circuit 116 compares the output voltage of the rectifiercircuit 108 with the output voltage of the capacitor 106. When theoutput voltage of the rectifier circuit 108 is lower than that of thecapacitor 106, the control circuit 116 controls the capacitor 106 andthe power supply circuit 114 to be connected. When the output voltage ofthe rectifier circuit 108 is higher than that of the capacitor 106, thecontrol circuit 116 operates so that the output of the rectifier circuit108 is input to the power supply circuit 114. In other words, thecontrol circuit 116 controls the direction of current in accordance withthe voltage output from the rectifier circuit 108 and the voltage outputfrom the capacitor 106.

Moreover, as shown in FIG. 8 of Embodiment 3, the power isintermittently supplied from the capacitor 106 to the load 118 throughthe power supply circuit 114, whereby the amount of power consumptioncan be reduced. Furthermore, a plurality of antennas may be provided asshown in Embodiment 4.

In the power storage device of this embodiment, power of anelectromagnetic wave received at the antenna and power stored in thecapacitor are compared by the control circuit depending on a receptionstate of an electromagnetic wave, whereby a path of power supplied tothe load can be selected. Accordingly, the power stored in the capacitorcan be efficiently utilized, and the power can be stably supplied to theload.

EMBODIMENT 6

This embodiment will describe a transistor that can be applied to thepower supply control circuit 14 in Embodiments 1 to 5.

FIG. 17 shows a thin film transistor formed over a substrate 178 havingan insulating surface. A glass substrate such as aluminosilicate glass,a quartz substrate, or the like can be employed as the substrate. Thethickness of the substrate 178 is 400 μm to 700 μm; however, thesubstrate may be polished to have a thin thickness of 5 μm to 100 μm.This is because the mechanical strength can be maintained by using thesubstrate with the second structural body as shown in Embodiments 1 to3.

A first insulating layer 180 may be formed using silicon nitride orsilicon oxide over the substrate 178. The first insulating layer 180 hasan effect for stabilizing characteristics of the thin film transistor. Asemiconductor layer 182 is preferably polycrystalline silicon.Alternatively, the semiconductor layer 182 may be a single crystallinesilicon thin film, of which a crystal grain boundary does not affectdrift of carriers in a channel formation region overlapping with a gateelectrode 186.

As another structure, the substrate 178 may be formed using a siliconsemiconductor, and the first insulating layer 180 may be formed usingsilicon oxide. In this case, the semiconductor layer 182 can be formedusing single crystalline silicon. In other words, a SOI (Silicon onInsulator) substrate can be used.

The gate electrode 186 is formed over the semiconductor layer 182 with agate insulating layer 184 interposed therebetween. Sidewalls may beformed on opposite sides of the gate electrode 186, and a lightly dopeddrain may be formed in the semiconductor layer 182 by the sidewalls. Asecond insulating layer 188 is formed using silicon oxide and siliconoxynitiride. The second insulating layer 188 is a so-called interlayerinsulating layer, and a first wiring 190 is formed thereover. The firstwiring 190 is connected to a source region and a drain region formed inthe semiconductor layer 182.

A third insulating layer 192 is formed using silicon nitride, siliconoxynitiride, silicon oxide, or the like, and a second wiring 194 isformed. Although the first wiring 190 and the second wiring 194 areshown in FIG. 17, the number of wirings to be stacked may be selected asappropriate, depending on the circuit structures. As for a wiringstructure, an embedded plug may be formed by selective growth oftungsten in a contact hole, or a copper wiring may be formed by adamascene process.

A connection electrode 24 is exposed on an outermost surface of thepower supply control circuit 14. The other region than the connectionelectrode 24 is covered with a fourth insulating layer 196, for example,so as not to expose the second wiring 194. The fourth insulating layer196 is preferably formed using silicon oxide that is formed by coatingin order to planarize a surface thereof. The connection electrode 24 isformed by forming a bump of copper or gold by a printing method or aplating method so as to lower contact resistance thereof.

As described above, an integrated circuit includes a thin filmtransistor, whereby the power supply control circuit 14 that operates byreceiving a communication signal in a microwave band (2.45 GHz) from anRF band (typically, 13.56 MHz) can be formed.

EMBODIMENT 7

This embodiment will describe another structure of the transistor thatis applied to the power supply control circuit 14 in Embodiments 1 to 5shown in FIG. 18. Note that a portion having the same function as thatof Embodiment 6 is denoted by the same reference numeral.

FIG. 18 shows a MOS (Metal Oxide Semiconductor) transistor, which isformed utilizing a semiconductor substrate 198. A single crystallinesilicon substrate is typically employed as the semiconductor substrate198. The thickness of the substrate 198 is 100 μm to 300 μm; however,the substrate 198 may be polished to be as thin as 10 μm to 100 μm. Thisis because the mechanical strength can be maintained when the substrateis used with the second structural body 12 as shown in Embodiments 1 to3.

An element isolation-insulating layer 200 is formed over thesemiconductor substrate 198. The element isolation-insulating layer 200can be formed using a LOCOS (Local Oxidation of Silicon) technique, inwhich a mask such as a nitride film is formed over the semiconductorsubstrate 198 and is thermally oxidized to be an oxide film for elementisolation. Alternatively, the element isolation-insulating layer 200 maybe formed by using a STI (Shallow Trench Isolation) technique in which agroove in the semiconductor substrate 198 is formed and an insulatingfilm is embedded therein and is planarized. When the STI technique isused, the element isolation insulating layer 200 can have a steep sidewalls, and the distance for element isolation can be reduced.

An n-well 202 and a p-well 204 are formed in the semiconductor substrate198, and accordingly, a so-called double well structure can be formed,in which an n-channel transistor and a p-channel transistor areincluded. Alternatively, a single-well structure may be used. A gateinsulating layer 184, a gate electrode 186, a second insulating layer188, a first wiring 190, a third insulating layer 192, a second wiring194, a connection electrode 24, and a fourth insulating layer 196 aresimilar to those of Embodiment 6.

As described above, an integrated circuit includes a MOS transistor,whereby the power supply control circuit 14 can be formed, whichoperates by receiving a communication signal in a microwave (2.45 GHz)band from an RF band (typically, 13.56 MHz).

EMBODIMENT 8

This embodiment describes an example of a so-called active wireless tagin which an IC (integrated circuit) with a sensor and a power storagedevice that supplies driving power to the IC with a sensor are providedwhich is shown in FIG. 19.

This active wireless tag is provided with an IC 206 with a sensor and apower storage device 100. The power storage device 100 includes anantenna 102, a power supply control circuit 104, and a capacitor 106.

In the power storage device 100, an electromagnetic wave received at theantenna 102 generates induced electromotive force at a resonance circuit107. The induced electromotive force is stored in the capacitor 106through a rectifier circuit 108. When power is supplied to the IC 206with a sensor, the power is output after an output voltage is stabilizedby a constant voltage circuit 109.

In the IC 206 with a sensor, a sensor portion 220 has a function fordetecting temperature, humidity, illuminance, and other characteristicsby a physical or chemical means. The sensor portion 220 includes asensor 210 and a sensor driving circuit 219 for controlling the sensor210. The sensor 210 is formed using a semiconductor element such as aresistor element, a capacitive coupling element, an inductive couplingelement, a photovoltaic element, a photoelectric conversion element, athermoelectric element, a transistor, a thermistor, a diode, or thelike. The sensor driving circuit 219 detects changes in impedance,reactance, inductance, a voltage or current; converts signals fromanalog to digital (A/D conversion); and outputs the signals to a controlcircuit 214.

A memory portion 218 is provided with a read-only memory and arewritable memory. The memory portion 218 is formed of a static RAM, anEEPROM (Electrically Erasable Programmable Read-Only Memory), a flashmemory, or the like, whereby information received through the sensorportion 220 and an antenna 208 can be recorded as needed. In order tomemorize the obtained data in the sensor portion 220, the memory portion218 preferably includes a nonvolatile memory that is capable ofsequentially writing and holding the memorized data. Further, a programfor making the sensor portion 220 operate may be memorized in the memoryportion 218. While the program is practiced, the sensor portion 220 canoperate at the timing that is set in advance to obtain data withoutsending a control signal from outside.

A communication circuit 212 includes a demodulation circuit 211 and amodulation circuit 213. The demodulation circuit 211 demodulates asignal that is input via the antenna 208 and outputs the signal to thecontrol circuit 214. The signal includes a signal for controlling thesensor portion 220 and/or information to be memorized in the memoryportion 218. A signal output from the sensor driving circuit 219 andinformation that is read from the memory portion 218 are output to themodulation circuit 213 via the control circuit 214. The modulationcircuit 213 modulates the signal into a signal capable of wirelesscommunication and outputs the signal to the external device via theantenna 208.

Power necessary for operation of the control circuit 214, the sensorportion 220, the memory portion 218, and the communication circuit 212is supplied from the power storage device 100. A power supply circuit216 transforms the power supplied from the power storage device 100 intoa predetermined voltage and supplies the voltage to each circuit. Forexample, in a case where data is written in the above nonvolatilememory, a voltage is temporary boosted to 10V to 20V. Further, a clocksignal is generated for making the control circuit operate.

As described above, by using the power storage device 100 with the IC206 with a sensor, the sensor portion is effectively utilized, andinformation can be obtained wirelessly to be memorized.

FIG. 20 shows an example of distribution management using an activewireless tag 230. The active wireless tag 230 includes the IC with asensor and the power storage device shown in FIG. 19. This activewireless tag 230 is attached to a packing box 228 containing products229. A product management system 222 comprises a computer 224 and acommunication device 226 connected to the computer 224, and the system222 is used for management of the active wireless tag 230. Thecommunication devices 226 can be located in each portion where theproducts are distributed, by using the communication network.

The distribution management can employ various modes. For example, whena temperature sensor, a humidity sensor, a light sensor, or the like isused as a sensor of the active wireless tag 230, the environments wherethe packing box 228 is kept during the distribution process can bemanaged. In this case, the power storage device is provided for theactive wireless tag 230; therefore, the sensor can operate at a giventiming independently from a control signal from the communication device226, and the environment data can be obtained. Furthermore, even whenthe distance between the communication device 226 and the activewireless tag 230 is large, the communication distance can be increasedwith the use of power of the power storage device.

As described, the active wireless tag provided with the IC with a sensorand the power storage device is used, whereby a variety of informationis obtained wirelessly with sensors, and the information can be managedby the computer.

(Additional Note)

As described above, the present invention includes at least thefollowing structure.

An aspect of the present invention is a power storage device including afirst structural body provided with an antenna, a power supply controlcircuit formed using a semiconductor layer interposed between insulatinglayers that are provided over and below the semiconductor layer, and asecond structural body provided with a capacitor and having higherrigidity than the first structural body, where the antenna and the powersupply control circuit are connected with a through electrode formed inthe second structural body, the power supply control circuit includes arectifier circuit, a switching circuit, a low-frequency signalgeneration circuit, and a power supply circuit, and the switchingcircuit controls power that is supplied from the capacitor or theantenna to the power supply circuit in accordance with a signal from thelow-frequency signal generation circuit.

Another aspect of the present invention is a power storage deviceincluding a first structural body provided with an antenna, a powersupply control circuit formed using a semiconductor layer interposedbetween insulating layers that are provided over and below thesemiconductor layer, and a second structural body provided with acapacitor and having higher rigidity than the first structural body,where the antenna and the power supply control circuit are connectedwith a through electrode formed in the second structural body, the powersupply control circuit includes a rectifier circuit, a control circuit,a switching circuit, a low-frequency signal generation circuit, and apower supply circuit, the control circuit selects power that is outputto the switching circuit by comparing power supplied from the antennawith power supplied from the capacitor, and the switching circuitoutputs the power selected by the control circuit to the power supplycircuit in accordance with a signal from the low-frequency signalgeneration circuit.

Another aspect of the present invention is a power storage deviceincluding a first structural body provided with an antenna, a powersupply control circuit formed using a semiconductor layer interposedbetween insulating layers that are provided over and below thesemiconductor layer, and a second structural body provided with acapacitor and having higher rigidity than the first structural body,where the power supply control circuit has a connection portion of theantenna and the capacitor, which is interposed between the firststructural body and the second structural body, the power supply controlcircuit includes a rectifier circuit, a switching circuit, alow-frequency signal generation circuit, and a power supply circuit, andthe switching circuit controls power that is supplied from the capacitoror the antenna to the power supply circuit in accordance with a signalfrom the low-frequency signal generation circuit.

Another aspect of the present invention is a power storage deviceincluding a first structural body provided with an antenna, a powersupply control circuit formed using a semiconductor layer interposedbetween insulating layers that are provided over and below thesemiconductor layer, and a second structural body provided with acapacitor and has higher rigidity than the first structural body, wherethe power supply control circuit having a connection portion of theantenna and the capacitor, which is interposed between the firststructural body and the second structural body, the power supply controlcircuit includes a rectifier circuit, a control circuit, a switchingcircuit, a low-frequency signal generation circuit, and a power supplycircuit, the control circuit selects power that is output to theswitching circuit by comparing power supplied from the antenna withpower supplied from the capacitor, and the switching circuit controls anoutput of power to the power supply circuit, which is selected by thecontrol circuit in accordance with a signal from the low-frequencysignal generation circuit.

This application is based on Japanese Patent Application serial no.2006-206939 filed in Japan Patent Office on Jul. 28, 2006, the entirecontents of which are hereby incorporated by reference.

1. A power storage device comprising: a first structural body having anantenna; a power supply control circuit having a semiconductor layerinterposed between an insulating layer over the semiconductor layer andan insulating layer below the semiconductor layer; and a secondstructural body having a capacitor and a through electrode, the throughelectrode formed through the second structural body, wherein the antennaand the power supply control circuit are connected with the throughelectrode, and wherein the second structural body has higher rigiditythan the first structural body.
 2. A power storage device comprising: afirst structural body having an antenna; a power supply control circuithaving a semiconductor layer interposed between an insulating layer overthe semiconductor layer and an insulating layer below the semiconductorlayer, the power supply control circuit comprising a rectifier circuit,a switching circuit, a low-frequency signal generation circuit, and apower supply circuit; and a second structural body having a capacitorand a through electrode, the through electrode formed through the secondstructural body, wherein the antenna and the power supply controlcircuit are connected with the through electrode, wherein the switchingcircuit controls power that is supplied from the capacitor or theantenna to the power supply circuit in accordance with a signal from thelow-frequency signal generation circuit, and wherein the secondstructural body has higher rigidity than the first structural body.
 3. Apower storage device comprising: a first structural body having anantenna; a second structural body having a capacitor and higher rigiditythan the first structural body; and a power supply control circuithaving a first connection electrode for connecting with the antenna anda second connection electrode for connecting with the capacitor, thepower supply control circuit interposed between the first structuralbody and the second structural body, wherein the power supply controlcircuit comprises a rectifier circuit, a switching circuit, alow-frequency signal generation circuit, and a power supply circuit, andwherein the switching circuit controls power that is supplied from thecapacitor or the antenna to the power supply circuit in accordance witha signal from the low-frequency signal generation circuit.
 4. A powerstorage device according to claim 2, further comprising: a controlcircuit in the power supply control circuit, wherein the control circuitselects a signal from the capacitor when power supplied form therectifier circuit is smaller than power supplied from the capacitor andthe control circuit selects a signal from the rectifier circuit when thepower supplied from the rectifier circuit is larger than the powersupplied from the capacitor.
 5. A power storage device according toclaim 3, further comprising: a control circuit in the power supplycontrol circuit, wherein the control circuit selects a signal from thecapacitor when power supplied form the rectifier circuit is smaller thanpower supplied from the capacitor and the control circuit selects asignal from the rectifier circuit when the power supplied from therectifier circuit is larger than the power supplied from the capacitor.6. A power storage device according to claim 1, wherein the capacitorhas a structure in which a dielectric layer and a capacitor electrodeare alternately stacked.
 7. A power storage device according to claim 2,wherein the capacitor has a structure in which a dielectric layer and acapacitor electrode are alternately stacked.
 8. A power storage deviceaccording to claim 3, wherein the capacitor has a structure in which adielectric layer and a capacitor electrode are alternately stacked.
 9. Apower storage device according to claim 1, wherein the first structuralbody comprises a plastic sheet, a plastic film, a glass epoxy resin, aglass plate, paper, or a nonwoven fabric.
 10. A power storage deviceaccording to claim 2, wherein the first structural body comprises aplastic sheet, a plastic film, a glass epoxy resin, a glass plate,paper, or a nonwoven fabric.
 11. A power storage device according toclaim 3, wherein the first structural body comprises a plastic sheet, aplastic film, a glass epoxy resin, a glass plate, paper, or a nonwovenfabric.
 12. A power storage device according to claim 1, wherein thesecond structural body comprises a ceramic material.
 13. A power storagedevice according to claim 2, wherein the second structural bodycomprises a ceramic material.
 14. A power storage device according toclaim 3, wherein the second structural body comprises a ceramicmaterial.
 15. A power storage device according to claim 1, wherein thepower supply control circuit comprises a plurality of transistors.
 16. Apower storage device according to claim 2, wherein the power supplycontrol circuit comprises a plurality of transistors.
 17. A powerstorage device according to claim 3, wherein the power supply controlcircuit comprises a plurality of transistors.